Vibration damping headlamp mounting system

ABSTRACT

A headlamp assembly for mounting a headlamp structure on a vehicle frame in a manner to minimize the vibration transmitted to the headlamp. The assembly includes an annular base member that is mounted to the vehicle frame with an opening sufficiently large to receive and surround the base of the headlamp structure without touching the base of the headlamp structure. A plurality of flat metal springs are attached by one end to the annular base at regular spaced intervals and the headlamp structure is attached to the other end of the shaped, flat springs. The springs hold the headlamp structure within the annular base substantially isolated from vibrations that would injure the filaments.

GOVERNMENT INTEREST

[0001] The invention described here may be made, used and licensed toothers by the United States Government for governmental purposes withoutpaying me any royalty.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] In one aspect this invention relates to headlamp mountingstructures. In a further aspect, this invention relates to a lowvibration rate headlamp mounting for use on off road vehicles.

[0004] 2. Prior Art

[0005] In general, military vehicles have unusual usage requirements.Therefore, they have evolved certain structural characteristics that areunique to the genre. In these vehicles, the headlamps and theirsupporting structure must allow normal highway travel yet be ruggedenough to travel cross-country over substantial distances. Also, thelights must be mounted so they are suitably positioned with respect tothe ground for both road and cross-country travel under combatconditions. One structural characteristic these vehicles have evolved isthe mounting structure used with their headlights. To meet the operatingrequirements of the medium and heavy-duty trucks used in the militaryfleet, the headlamps are mounted low on the body. Because of theheadlamps rugged, heavy structure, they have evolved to being mounteddirectly on the vehicle frame or bumper for many applications. Thisallows a solid mounting structure that adequately supports theheadlamp's weight.

[0006] Mounting the headlamps and associated structure directly on thevehicle frame makes for a solid mounting, but exposes the headlamps tosubstantial first and second order vibrations when the vehicle traversesrough terrain or roads. A second problem is engine vibration. The dieselengines used in the military fleet create continuous standing vibrationsin the headlamps even when the truck is at idle. The result is headlampsmounted on frame or bumper members have filaments that are constantlysubjected to vibration. The constant engine vibration combines with theshocks from vehicle operation to create a short filament life span. Inmany cases under peacekeeping or battle conditions, the headlamps aredestroyed in less than two weeks. To the military this constant headlampfailure is a severe problem. It lowers readiness, increases maintenancecosts, and increases risk to the soldier.

[0007] It is an object of this invention to provide a headlamp mountthat will isolate or substantially reduce the vehicle vibrations to theheadlamp in such a manner as to extend the lamp's life while maintainingthe standard military vehicle mounting characteristics.

SUMMARY OF THE INVENTION

[0008] Briefly, the present invention is a headlamp assembly formounting a headlamp structure on a vehicle frame in a manner to minimizethe vibration transmitted to the headlamp. The assembly includes anannular base member, which is mounted to the vehicle frame at thedesired location and has an opening sufficiently large to receive andsurround the base of the headlamp structure without touching the annularbase. A plurality of flat metal springs is used; each spring has one endattached to the annular base. The springs are attached at regularlyspaced intervals to the frame member.

[0009] A headlamp structure is attached to the other end of the shaped,flat springs. The springs will hold the headlamp structure to theannular base and substantially isolate the headlamp from vibrationscaused by vehicle operation that would injure the filaments.

BRIEF DESCRIPTION OF THE DRAWING

[0010] In the accompanying drawing:

[0011]FIG. 1 is an exploded view of one structure according to thisinvention; and

[0012]FIG. 2 is a side view in section of the assembly of FIG. 1.

DETAILED DESCRIPTION

[0013] Referring to the accompanying drawing in which like numeralsrefer to like parts and particularly to FIG. 1, a vibration dampingheadlamp assembly constructed in accordance with this invention isshown. An annular base member 10 is formed with a center opening 12 anda plurality of apertures circumferentially disposed about the rim. Theapertures are divided into two sets, a first set of frame mountingapertures 24 which are for attaching the base member 10 to a vehicleframe 16 or bumper. The remainder of the vehicle is not shown since suchstructures are well known. A first set of threaded fasteners 18 arepassed through the apertures 24 in the annular base 10 and mated withcomplimentary threaded nuts 20 disposed on the opposite side of vehicleframe 16, to securely attach the base to the vehicle.

[0014] The annular base 10 has a second set of threaded fasteners 26disposed in a second set of circumferentially disposed apertures 14 andmating with complimentary nuts 22. Each of the second set of threadedfasteners 26 also passes through an aperture in one leg of an associatedU-shaped flat spring 28, there being one spring for each threadedfastener 26. When the complimentary nuts 22 are tightened, one leg ofeach U-shaped flat spring 28 will be firmly attached to the annular base10. Tightening the first set of nuts 20 will draw the heads of bolts 18towards the vehicle wall 16 holding the second set of nuts 22 boltssecurely in position. The remaining, second leg of the U-shaped flatspring will extend parallel to the first leg and is spaced apart fromthe first leg.

[0015] The second leg of U-shaped flat spring 28 has an aperture thatreceives a threaded stud 30 that extends from a headlamp housing 34. Acomplimentary nut 32 engages the stud 30 to attach the headlamp housing34 firmly to U-shaped spring 28. A plurality of threaded fasteners 36hold the headlamp structure 38 to the headlamp housing 34.

[0016] As shown, there are three of the U-shaped flat springs 28circumferentially mounted on the annular base 10 at equal angles. It hasbeen found that three or more flat U-shaped springs 28 can effectivelysupport the headlamp housing 34 and isolate it from first and secondorder vibrations that tend to destroy the filaments of headlamp 38. Inconstructing the U-shaped springs 28 for heavy military transportsheadlamp assembly, it has been found that high carbon spring steel orhigh carbon stainless spring steel abut 0.015 to 0.025 thick, about 0.04to 0.06 in wide and having legs about 1.0 to 1.5 in long make anacceptable flat, U-shaped spring. The legs will be formed so they areseparated by about 0.35 to 0.5 in so fasteners and legs do not interactdue to the vibrations or displacement of the headlamp when the vehicleis operating under either normal or cross-country operating conditions.Springs made to this configuration will properly support the headlamphousing in coaxial alignment with the annular base member and reduce thevibration to an acceptable level that minimizes deleterious effects onthe headlamp.

[0017] If a headlamp 34 were normally mounted directly to the vehicleframe 16 of a medium sized military truck, it will be vibrated at afrequency of about 4500 cycles per second with a 0.004 inchdisplacement. The displacement velocity will be approximately 0.225inches per second. This degree of vibration is easily visible to anobserver and results in a frequent headlamp failure. Conversely whenmounted using the flat spring assembly of this invention using thedimensions above, the vibration was reduced to about 80-100 cycles persecond, with 0.0005 inch displacement and 0.030 inches per seconddisplacement velocity. This is approximately an 80% reduction invibration. The resulting vibration is so reduced it is not normallyperceptible to a human hand and headlamps show a normal operating lifecycle for headlamps mounted on the body of the truck.

[0018] Various alterations and modifications will become apparent tothose skilled in the art without departing from the scope and spirit ofthis invention and it is understood this invention is limited only bythe following claims.

What is claimed is:
 1. A headlamp mounting assembly for mounting aheadlamp to the frame of a vehicle including: an annular base membermounted on the vehicle frame; a plurality of flat, shaped springs havingfirst and second ends, the first end being attached to the annular basemember, the flat shaped springs being located at equally spacedintervals about the periphery of the annular base member; and a headlamphousing attached to the second end of the flat shaped springs; wherebythe flat shaped springs hold the headlamp housing to the annular basemember and serve to dampen vibrations to the headlamp housing.
 2. Aheadlamp mounting assembly for mounting a headlamp to the frame of avehicle including: an annular base member mounted on the vehicle frame;a plurality of flat U-shaped metal springs, each spring having first andsecond free ends the first end of each of the U-shaped springs beingattached to the annular base, the U-shaped springs being disposed on theannular base member at regular, equally spaced intervals about theannular base so as to provide an essentially constant spring rate alongany radial direction; a headlamp housing attached to the second freeends of each U-shaped spring the U-shaped spring serving to hold theheadlamp housing to the annular base member and serving to dampenvibratory energies applied to the housing to a level below that whichadversely effects the headlamp filaments.
 3. A headlamp mountingaccording to claim 2 wherein: The U-shaped springs are formed from highcarbon steel and having a thickness of about 0.015 to 0.025 inch, awidth of about 0.04 to 0.06 inch and legs about 1.0 to 1.5 inch long thelegs being separated about 0.35 to 0.5 inch.
 4. The headlamp mounting ofclaim 3 where the high carbon steel is stainless steel.
 5. A headlampmounting assembly for mounting a headlamp to the frame of a vehicleincluding: an annular base member mounted on the vehicle frame; aplurality of flat U-shaped metal springs, each spring having first andsecond free ends the first end of each of the U-shaped springs beingattached to the annular base, the U-shaped springs being disposed on theannular base member at regular, equally spaced intervals about theannular base so as to provide an essentially constant spring rate alongany radial direction; a headlamp housing attached to the second freeends of each U-shaped spring the U-shaped spring serving to hold theheadlamp housing to the annular base member in coaxial alignment withthe annular base member and serving to dampen vibratory energies appliedto the housing to a level below that which adversely effects theheadlamp filaments.